Re: st: meta analysis modelling and regression in stata

[David Hoaglin <dchoaglin@gmail.com>]

Hi, Azreen.

I have not been following this discussion closely, but it is not yet
clear to me that your data are suitable for meta-analysis.

Please explain the nature of the percentage change, and what it means
that "all values are grouped under Y."

You mentioned regression as the method that one of the papers used.
How did that paper  use regression, what variables were in its
regression model, and how did it report the results?

A common concern in meta-analysis is whether the individual studies
are sufficiently similar.  If the various papers differ in the outcome
variables for which they report change and differ in the methods that
they use, the results that they report may not be usable in a
meta-analysis.

David Hoaglin

On Sun, Nov 10, 2013 at 6:12 PM, Azreen Karim <azreen_nsu@yahoo.com> wrote:
> Hi all,
>
> Its been really great to get some really good comments on this issue. I would like to start from the point where people seems to agree - that meta analysis is basically done on a weighted average of effect sizes. In my current project, all of my data regarding the dependent variable are in percentage changes i.e. I have taken percentage changes in income, consumption and other variables. I think the weighted problem has been taken care through this as all of these numbers are out of 100 (same weight). The basic problem is, I am still confused which model should I go for in my case? and as I am new to stata, how am I going to write down the regression commands? my meta dataset has got the following format:
>
> Y paper income consumption poverty wealth health labor education hhcommunity time region demographic socioeconomic geognature method disaster
>
> -9.7/ 3 /3 /0 /0 /0 /0 /0 /0 /0 /0 /0 /0 /1 /0 /1 /1
> -7.56 /4 /3 /0 /0 /0 /0 /0 /0 /1 /0 /1 /0 /1 /0 /1 /2
> -3.08 /1/4 /3 /0 /0 /0 /0 /0 /0 /1 /1 /1 /0 /1 /0 /1 /1
>
> Here, to describe the first line of the dataset, -9.7 is the value from paper 3, 3 is the type of income (e.g.farm income)and this is an income value the rest are 0s, method 1 means here regression(the type of method the paper has used) and disaster 1 means the specific type of disaster (e.g. flood). Therefore, all values are grouped under Y (they are all taken in percentage terms) and the subsequent variables represent the types of variables that I have defined. I am going to look at the impacts of disasters on all these variables and their types separately. The dependent variables are from Y till education, from hhcommunity to geognature are the controls (written in binary format whether diffrent papers put these controls or not, method and disaster are the independent variable. This study is to look at the impacts of disasters on different poverty variables taken from different studies.
>
> I am still confused whether I need the metan command or not? or I could simply do the regression straight away? which model should be better? and how to write the commands in stata?
>
> Cheers,
> Azreen.

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